Arc Fault Circuit Interrupter (AFCI) devices are configured to recognize arcing conditions in electrical wiring systems and interrupt current flow to extinguish arcing. At the same time, AFCI systems or devices need to be resistant to nuisance tripping, which may be caused by noise produced by electrical motors, switches, dimmers and other devices operating normally.
There are generally two types of arc faults, series arc faults and parallel arc faults. A series arc fault is in series with the load and thus cannot have a current value that is greater than the load current. Whereas, parallel arc faults may occur between any pairing of phase and neutral conductive paths, phase and ground conductive paths, or neutral and ground conductive paths. In contrast to series arc faults, the current value in parallel arc faults is not limited by the load and as a result, the current in parallel arc faults can potentially be much greater.
In the case of a parallel arc fault to ground, such an arc fault may be cleared either by a typical ground fault circuit interrupter (GFCI) or an AFCI.
Both series and parallel arc faults can serve as a source of ignition of surrounding combustible materials.
This application also incorporates by reference in their entirety the following U.S. patents: U.S. Pat. No. 7,986,148 which issued on Jul. 26, 2011 to Mernyk et al; U.S. Pat. No. 7,535,234 which issued on May 19, 2009 to Mernyk et al; U.S. Pat. No. 7,259,568 which issued on Aug. 21, 2007 to Mernyk et al; and U.S. Pat. No. 6,972,572 which issued on Dec. 6, 2005 to Mernyk et al.